Method and apparatus for producing face clutches



E. WILDHABER June 29, 1954 METHOD AND APPARATUS FOR PRODUCING FACE CLUTCHES v 2 Sheets-Sheet 1 Original Filed Aug. 4, 1945 INVENTOR. ERA/E57 W/LDHABER -w-wn ATTORNEY June 29, 1954 E- Wfl-UHABER METHOD AND APPARATUS FOR PRODUCING FACE CLUTCHES Original Filed Aug. 4, 1945 2 Sheets-Sheet 2 512N155 T VV/LDHAIEEIQ;

INVENTOR.

ATTORNEY Patented June 29, 1954 UNITED STATES ATENT OFFICE METHOD AND APPARATUS FOR PRODUCING FACE CLUTCHES Ernest Wildhaber, Brighton, N. Y., assignor to Gleason Works, Rochester, N. Y., a corporation of New York Claims. 1

The present invention relates to a method and apparatus. for producing toothed face members, such as couplings and clutches, and is a division of my copending application Serial No. 608,853, filed August 4, 1945, now Patent No. 2,558,203, ranted June 26, 1951. In some aspects the invention constitutes an improvement over the inventions of my prior Patents Nos. 2,384,582 and 2,427,641 which were copending with said application Serial No. 608,853.

In my prior patents, a method is disclosed for producing toothed face clutches and couplings in which a face mill cutter is so positioned as to operate simultaneously in two spaced tooth zones of a coupling or clutch member and cut simultaneously opposite sides of spaced teeth of the work. The cutting operation is performed by rotating the cutter on its axis and effecting a relative depthwise feed movement between the cutter and work in the direction of tooth depth. When the cutter reaches full depth position, opposite sides of a pair of spaced teeth of the work will be finished. The cutter is then withdrawn from engagement with the work, and the work indexed. Then the feed movement is begun anew to cause the cutter to finish opposite sides of another pair of spaced teeth. The two sides of each tooth space of the work are cut, therefore, in separate cycles, one side and part of the bottom of a tooth space being cut when the tooth space is in one zone of cut and the opposite side and the rest of the bottom of the tooth space being cut when the tooth space is in the other zone of cut. The cutter is so positioned relative to the work as to cut tooth spaces on the work which are of greater width at their outer ends than at their inner ends. In most cases, also, the cutting blades are made with rounded corhers at the junctures of their side and tip cutting edges so as to produce rounds in the tooth spaces at. the juncture of the sides and bottoms of the tooth spaces for greater tooth strength. The tip-cutting edges of the cutter are so inclined to the side-cutting edges of the cutter as to have thepurpose of producing bottoms in the finish-ed tooth spaces which are single surfaces, for instance, plane or conical surfaces, and in order to be certain of completely cutting the bottoms of the tooth spaces, the tip-cutting edges of the cutter have been made of such width that the two cuts taken in a tooth space overlap somewhat all along the tooth space.

Where used in this description the terms tipcutting edges and side-cutting edges will be understood to refer to the tip-cutting and sidecutting profiles of the tool, or, more strictly, the profiles of the paths that are swept by the cutting edges of the tool, because the invention is concerned with these profiles rather than with the angular dispositions of the actual cutting edges. In the case of a bladed tool the disposition of the actual edges may vary from the cutting profiles referred to by reason of rake angle and the like, while in the case of an abrasive tool the minute cutting edges thereof may extend in various directions, these being matters with which the present invention is not directly concerned.

It has been found in practice that couplings and clutches produced in this way have scratches in the bottoms of the tooth spaces in the area of overlap of the two outs. In the bottoms of some of the tooth spaces, the first cut predominates and in the bottoms of other tooth spaces the second cut predominates. The predominance of one cut over the other is probably due to the fact that the angle through which the work has to be indexed to eifect the two outs in a tooth space causes even the slightest inaccuracy in the mounting of the cutter or of the work to be magnified, and, moreover, difierent reactions to elastic deflections occur during the two cuts, even though very slight. The predominance of one cut over the other not only gives a bad appearance to the clutch or coupling member, but, where one cut is slightly deeper than the other, a gouge is produced. This is a serious objection, because a gouge is always an incipient source of cracks, and cracks are dangerous especially where the clutch or coupling is heavily loaded as is the case in aeronautical installations.

Further than this, with prior construction and prior methods of production the face width of the Work, that is, the length of its teeth is definitely limited especially in cases Where rounds are formed at the junctures of the sides and bottoms of the tooth spaces. This is because the tip-cutting edge of the tool always has to be made of sufficient width to out half of the large end of the tooth space plus some overlap, and if the tooth space is too long then the tip-cutting edge will interfere, at the small end of the tooth space, with the round formed on the side of the tooth space opposite to the side being cut.

The present invention has for its primary ob jects to provide a method and apparatus for producing toothed face clutch and coupling members, through which such members can be out without danger of gouging the bottoms of the tooth spaces and through which clutch or cou- 3 pling members of much greater tooth length than out heretofore may be cut with rounds at the junctures of the Sides and bottoms of the tooth spaces.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the drawings:

Fig. l is a fragmentary elevational view of a pair of coupling members made according to one embodiment of this invention;

Fig. 2 is a sectional view showing one of the coupling members in section in the pitch plane and illustrating the method of cutting this coupling member;

Fig. 3 is a part elevational, part sectional view taken at right angles to Fig. 2, and further illustrating the structure of this coupling member and the method of cutting it;

Figs. 4 and 5 are views, corresponding to Figs. 2 and 3, respectively, and illustrating the structure and one method of cutting the mating coupling member;

Fig. 6 is a diagrammatic view on an enlarged scale further illustrating the invention and showing particularly the relative positions of the cutter and the work at the inner end of a tooth space of the work during cutting of one side of the tooth space of the coupling member shown in Figs. 2 and 3;

Fig. 7 is a similar view but showing the relative positions of the cutter and the work during the cutting of the large end of this tooth space;

Fig. 8 is a diagrammatic view illustrating the cutting of a coupling member constructed according to another embodiment of the invention and showing particularly the relation of the cutter and the work during the cutting of one side of a tooth space of this member at the inner end thereof; and

Fig. 9 is a similar view showing the relation of the cutter and the work during cutting at the outer end of this same side of the tooth space of the work.

In Figs. 1 to 7 inclusive, Ill and H denote the two members of a coupling made according to one embodiment of this invention. The teeth !2 of the member [0 have opposite side tooth surfaces [3 and M which are longitudinall concave and which are of zero pressure angle, that is, extend in the direction of the axis Id of the coupling. The teeth ii of the member II have opposite side tooth surfaces l8 and [9 which are longitudinally convex, but which, like the sides of the teeth of the member Ill, are of zero pressure angle, extending in the direction of the axis of the coupling. The teeth and tooth spaces of both members extend generally radially of the clutch axis I5, the sides of the teeth being radial of the axis I5 at mean points in their length. Thus, a side l3a of clutch member It] is tangent, at a mean point in the length of the tooth side, to line drawn radial of the clutch axis IS.

The tooth surfaces of the two members It) and II may be out according to the basic principles disclosed in my applications above mentioned. For cutting the sides and bottoms of the tooth spaces of the coupling member Ii), a face mill cutter or annular grinding wheel is employed that has outside cutting edges 25 and tip-cutting edges 5|, and for cutting the sides and bottoms of the tooth spaces of the coupling member I l, a face mill cutter or grinding wheel 85 is employed that has inside cutting edges 86 and tip-cutting edges 9|. Each cutter is positioned to operate 4 simultaneously in two spaced tooth zones of the work and cut simultaneously opposite sides of spaced teeth of the work as the cutter is rotated in engagement with the work and simultaneously fed into depth.

In the instance shown, the outside cutting edges 26 of tool 25 are of positive pressure angle, and axis of the tool is inclined inwardly with reference to the pitch plane 28 of the coupling member Ill so that the tool will produce side tooth surfaces l3 and I4 on the teeth l2 of the work which are of zero pressure angle. Similarly, the tool has inside cutting edges 86 which are of positive pressure angle and the tool is tilted outwardly with reference to the work so that its axis 8'! is inclined to pitch plane 28 at the angle required to produce side tooth surfaces on the work which are of zero pressure angle,

In the embodiment of the invention shown, the sides of the teeth of both coupling members are rounded at their junctures with the tips of the teeth. Thus, the opposite sides of the teeth of coupling member H! are rounded at 32 and 33 as illustrated in Fig. 7, To produce these rounds, the outside surface of tool 25 is rounded at the point where the side-cutting edge or side-cutting surface of the tool joins the body of the tool, as denoted at 29. Likewise, tool 85 is rounded at 89.

To produce the rounds desired at the junctures of the sides of the teeth and the bottoms of the tooth spaces, the cutting tool will have a corresponding round formed at the juncture of its side and tip-cutting edges. Thus, as shown in Figs. 6 and '7 rounds 35 and 36, respectively, are provided on the coupling member Hi at the junctures of opposite sides I3 and [4 of its teeth and the bottom of its tooth spaces. These rounds are of circular arcuate shape and in the section of Fig. 6 have their centers at 31 and 38, respectively. The tool 25 accordingly has a round 34 formed at the juncture of its side and tip-cutting edges whose radius is equal to the radius of the rounds 35 and 35 to be produced. The tool 85 is formed with a. corresponding round 94 at the juncture of its inside cutting edge or edges t6 and its tipcutting edge or edges 9|.

The path of travel of the tip of the tool 25 in the cutting of opposite side tooth surfaces [3a and Ma of spaced teeth 12a and I2?) of the member IQ is denoted by lines 25' and 25" in Fig. 2 while the path of travel of the tip of tool 85 in the cutting of a pair of opposite side tooth surfaces of spaced teeth. of coupling member II is denoted by lines 85 and 85 in Fig. 4. In either case, when a pair of tooth sides have been cut, the tool is withdrawn from engagement with the work and the work indexed. Then opposite sides of another pair of spaced teeth is out. As the work is indexed around, the tool will take two cuts in each tooth space, one during the cutting of one side of the tooth space and the other in the cutting of the opposite side of that tooth space.

The dotted lines 30 in Fig. 2 indicate the path of the tool in the cutting of one side of one of the tooth spaces of coupling member in and the dotted lines 3| denote the path of the tool in the cutting of the opposite side of that same tooth space. These two cutting paths have to overlap, otherwise the bottom of the tooth space would not be finished across its whole width especially at the large or outer end of the tooth space.

It has always been the aim heretofore to produce tooth space bottoms which are single, smooth, uninterrupted surfaces. Due to the two outs taken in the bottoms of the tooth spaces, however, and the overlap of these cuts, and the slight inaccuracies that can always occur in machines and their settings, this has been found virtually impossible. Whether it was the intention to produce tooth bottoms that were plane or were conical, one cut seems always to predominate the other in each tooth space bottom and cause a gouge.

Where it has been desired to produce teeth which are well rounded at the junctures of their sides with the bottoms of the tooth spaces, as is shown on large scale in Figs. 6 and '7, still further difficulties have been encountered. In cutting a tooth space of the clutch member Ill according to prior practice, a cutting tool would be employed whose tip-cutting edge in full depth position would occupy the position denoted in dotted lines at 40 in Figs. 6 and '7, and the cut taken by thetip-cutting edge 4i] of the tool would be plane or conical depending upon whether the tip-cutting edge 45} was inclined at right angles or at other than right angles to the axis of the cutter. To produce the round 35 at one side of the tooth space and a plane or conical bottom land and avoid having the tip-cutting edge 40 cut into the round 36 at the opposite side of the tooth space at the small end of the tooth space, the right hand end of the cutting profile of the tool had to begin at or but slightly beyond the projection of the point 38 to the tooth space bottom at the small end of the tooth space. That is, with prior practice the right hand side of the cutting profile had to extend along some line such as the line 4|, close to the projection of point 38 to the tip-cutting edge 40. The line 4|, however, extends only a moderate distance beyond the center line 42 of the tooth space. This means that with prior practice couplings or clutches of short face width only could be produced, since if the length of teeth from end to end was such that the width of the tooth spaces at their out side ends was greater than twice the width of the tip-cutting edge 4B of the tool, the bottoms of the tooth spaces could not be finished for their full width at the outer ends of the tooth spaces, and a separate operation would be required to complete the bottoms of the tooth spaces.

The diiiiculties previously encountered are overcome with the present invention by making the bottoms of the tooth spaces of ridge or roof shape, instead of trying'to make them a single plane or a single conical surface as was previously attempted. Thus, as clearly shown in Figs. 6 and '7, the bottoms of the tooth spaces of coupling member It are made up of two surfaces 44 and 45 which are inclined to one another and which join in a line 46 which extends longitudinally of the tooth space substantially centrally thereof. The bottoms of the tooth spaces, in other words are of V-shape in cross-section. The two parts of the bottom of a tooth space meet at an angle which differs from one hundred and eighty degrees by more than five degrees and which may be as high as twenty degrees,that is, each of the two sides 44 and 45 of the bottom of the tooth space may be inclined to a plane by as much as ten degrees per side. i

To cut tooth spaces according to this invention, the cutter used has its tip-cutting edge or edges so inclined to its side-cutting edge as to form the portions of the tooth bottom at the desired angle as the cutter revolves in engagement with the work at full depth. Thus, tip-cutting edge 5| of cutter 25 will be inclined to its side-cutting edge 26 at the angle required to produce bottom portions 44 and in the tooth spaces of the work, in the two cuts taken in each tooth space, which will be inclined to one another at the desired angle. Due to the inclination of the tipcutting edge 5| of the cutter, the tip-cutting edge can be made of much greater width than the tip-cutting edges of cutters heretofore employed. Thus, as shown in Figs. 6 and '7, tip-cutting edge 5| can be made of such width that the righthand side of the operating portion of the tool may be at 52, instead of at 4|, and, at the inner end of the tooth space, just clear the side of the tooth space opposite to the side on which the out is being taken. The tip-cutting edge 5| has simply to be inclined sufiiciently to avoid cutting into the round 3'5 formed at the opposite side l4 of the tooth space. It will be obvious that with the present invention couplings or clutches of much greater face width can be out than with prior practice, for with the present invention the tip-cutting edge 5| of the cutter can cut up to the center line 42 of the tooth space at the large end of the tooth space, as shown in Fig. '7, and the length of the tooth space can be longer because of the increased width of space that can be out at the outer end of the space.

In Figs. 6 and 7, the pitch line 28 is shown at a distance from the top of the teeth equal to half the working depth. It intersects the side profile l3 at a point 53 in Fig. 6 and the center line 42 of the tooth space at point 54. 55 denotes the projection of the right-hand end point of the tip-cutting edge 5| to the pitch line. The width of the tooth space at the small end equals twice the distance 5354. If the tool 25 has the cutting edge 5| shown, a tooth space can be produced which at its outer end has a width equal to twice the distance 5355 measured at the pitch line of the tooth space, as shown in Fig. 7 The outside width of a tooth space and the inside width of the tooth space are then substantially in the proportion of the distances 53-455 and 5354, which is quite acceptable.

When clutch or coupling members are cut according to the present invention, the cut in the bottom of the tooth space at one side of the tooth space clears the cut at the other side of the tooth space and the two outs join at the substantially centrally located ridge. Hence, there are no scratches or gouges formed in the bottom of the tooth space by reason of one out being taken at a slightly different height from the other, and a longer tooth can be out than in prior practice without an added operation.

The present invention may be practiced, of course, in the cutting of various typ s of clutches and couplings and is by no means confined to the cutting of clutches or couplings having side tooth surfaces of zero pressure angle. Thus, as shown in Figs. 8 and 9, the present invention may be used with advantage in the cutting of a clutch or coupling member Whose opposite side tooth surfaces El and 62 are of positive pressure angle. Here a tool 55 is employed whose side-cutting edge 66 is also of positive pressure angle. The tip-cutting edge of this tool is denoted at 67. In the embodiment shown, the sides of the teeth of the clutch or coupling member are rounded off at their junctures with the tips 66 of the teeth and with the bottoms of the tooth spaces. Accordingly, the cutting profile of the tool is so formed that it has a rounded cutting edge '69 between the side-cutting edge 66 and the body of the tool and a rounded cutting edge 10 joining the side-cutting edge '56 and the tip-cutting edge 61. Thus the necessary rounds will be formed on the teeth of the work. As in the previously described embodiment of the invention, the tipcutting edge 67 is inclined to the side-cutting edge 66 at such an angle as to produce bottom portions 12 and 73 in the bottoms of the tooth spaces which are inclined to one another and form a ridge M lying substantially in the center line of the tooth space. Again the tool can have a tip-cutting edge of greater width than previously used with its right-hand side positioned at 16 rather than at 18 which would be the limi position for a tool built according to previous practice and having its tip-cutting edge at 71. The result is that a tooth space of greater length can be out.

In Figs. '7 and 9, 49 and T9 denote, respectively, the position of the topof a tooth of the mating coupling member and show that the ridge formed in the bottom of the tooth space of one coupling member does not interfere with the tip of the tooth of the mating clutch or coupling member.

Moreover, while the invention has been described. in connection with the toothed members whose tooth sides are longitudinally curved, it will be obvious tha it may be applied also to toothed members whose tooth sides are longitudinally straight. For instance, it may be used on face coupling or clutch members having side tooth surfaces which are straight and radial of the coupling or clutch axis.

Still further, the invention is not confined to use in operations where the two portions of the bottoms of the tooth spaces are cut in one operation, but may be employed where one side of all of the teeth and tooth space bottoms are cut in one operation and the opposite sides of the teeth and tooth space bottoms are cut in a separate operation.

Throughout the specification and claims wherever the terms cutter or cutting are used, it will be understood that they may includ grinding wheels and grinding, for a grinding wheel is a cutter with an infinite number of cutting edges.

The foregoing description of several embodiments of the invention has been made to exemplify the inventive principles involved. These principles, of course, may also be utilized in various other modification-s of the method and apparatus without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. The method of cutting a toothed face member which comprises positioning a face mill cutter, that has a side-cutting profile and a tip-cutting profile, in engagement with the work so that the cutter will operate in two spaced tooth zones of the work simultaneously and its side-cutting profile will cut on opposite sides of spaced teeth of the work simultaneously, and rotating the cutter in engagement with the work while effecting a relative depthwise feed movement between the cutter and work to cut the tooth sides to full depth, then withdrawing the cutter from engagement with the work and indexing'the Work, and then repeating the operations unitl the opposite sides of all of the teeth of the work have been completed, the tip-cutting profile of the cutter being so inclined to it side-cutting profile that the bottoms of the finished tooth spaces are of generally inverted V-shape in cross section.

2. In the cutting of a toothed face member with a rotating cutter having a side-cutting profile and a tip-cutting profile, with the cutter so positioned relative to said member that during the same revolution it operates in two spaced tooth spaces and its side-cutting profile cuts opposite sides of two spaced teeth, the method comprising rotating the cutter in such position relative to said member that while in the cut its tip-cutting profile is inclined to the plane of the face of said member, the direction of the inclination being such that the tip-cutting profile cuts deeper at the end thereof adjacent the side-cutting profile than at the opposite end thereof.

3. In the cutting of a toothed face member with a rotating cutter having a side-cutting profile and a tip-cutting profile, with the cutter s0 positioned relative to said member that during the same revolution it operates in two spaced tooth spaces and its side-cutting profile cuts opposite sides of two spaced teeth, and, while so rotating the cutter, effecting a relative depthwise feed movement to cut the tooth sides to full depth, then effecting withdrawal of the cutter relative to the member and indexing the latter, and then repeating the operations until the opposite sides of all of the teeth have been completed, the method comprising rotating the cutter in such position relative to said member that its tip cutting profile while in the cut is inclined to the plane of the face of said member, the direction of the inclination being such that the tip-cutting profile cuts deeper at the end thereof adjacent the side-cutting profile than at the opposite end thereof.

4. The method of cutting a toothed face member with a rotary cutter having a side-cutting profile and a tip-cutting profile, said side-cutting profile producing both sides of the teeth, with the member indexed to different positions about its axis for the cutting of the opposite sides of each tooth space, by effecting a relative depthwise feed of the member and cutter while the latter is rotating in such position relative to the member that its tip-cutting profile, while in the cut, is inclined to the face of the member to cut to greater depth at its end adjacent the side cutting profile than at its opposite end, whereby the bottoms of the finished tooth spaces are of generally inverted V-shape in cross section.

5. Apparatus for cutting a toothed face member with a rotatable cutter having a side-cutting profile and a tip-cutting profile, the apparatus supporting the member for indexing motion about an axis to bring successive tooth spaces into position to be cut, the cutter being arranged to rotate about an axis lying substantially in the same plane as the axis of indexing motion so that during the same revolution the cutter operates in two spaced tooth spaces and its sidecutting profile cuts opposite sides of two spaced teeth, the tip-cutting profile being inclined to the cutter axis, the amount and direction of said inclination being such that, while in the cutting zones, the tip-cutting profile forms an acute angle with a plane perpendicular to the axis of indexing motion and cuts deeper at its end adjacent the side-cutting profile than at its opposite end, to thereby cut the bottoms of the tooth spaces of the member to a substantially inverted V-shape in cross section.

Name Date Wildhaber Mar. 30, 1943 Number 

